Steering device and forklift truck

Abstract

The invention provides a steering device and a forklift truck, wherein an actual steering angle is appropriately maintained at a target value without the need of mechanical contact. The actual steering angle, namely the detected steering angle, is set to be at the target value. According to the steering torque of the steering device (51), the steering torque of a steering wheel is decreased from the upper limit value to the lower limit value of a decrescent range of steering angles. When the target steering angle is reached, the inverse steering torque of the steering wheel is increased from the lower limit value to the upper limit value of a sharp range of steering angles narrower than the decrescent range of steering angles. In this way, the range of the steering angles of the varying steering torque is narrowed down upon the completion of the target steering angle, so that the variation rate of the steering torque is increased. As a result, compared with the steering torque before reaching the target value, the steering torque is increased sharply to the upper limit value.

Description

technical field [0001] The present invention relates to a steering device mounted on a forklift. Background technique [0002] Generally, in a steering device mounted on a forklift or the like, in order to stop the steering of the steering wheel at a predetermined final position, the steering wheel or its peripheral parts are configured to contact a structure serving as a brake. [0003] However, since a large steering torque corresponding to the operating torque of the steering gear is provided to the steering wheel in the steering gear device, a large cost burden is required in order to be configured to withstand the steering torque, and in recent years, In the past, since the impact when contacting a structure is also large, a technology related to a stop method without mechanical contact has also been proposed. [0004] Specifically, a technique has been proposed in which the steering angle at which the steering of the steering wheels should be stopped is set as a targe...

AI Technical Summary

Problems solved by technology

[0008] However, in this structure, if a large operating torque is continuously applied to the steering gear before and after the target steering angle is reached, the steering wheel may be steered to a point where the force intended to steer the steering wheel by the operating torque does not reach the target. The state of the steering angle in which the steering torque in the direction of the return of the steering angle is balanced by the steering angle

[0009] This is because the rate of change of the steering torque is kept constant before and after reaching the target steering angle, and the direction of the steering torque is smoothly changed to alleviate the impact. The steering torque in the returning direction can only be gradually increased at the same rate of change, and there is a range of steering angles in which the steering torque cannot be sufficiently increased

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